As an adjective trustworthy
is deserving of trust, reliable.
As a noun faithfulness is
the state of being faithful; allegiance; loyalty; fidelity.
trustworthy
English
Synonyms
* believable
* convincing
* credible
* dependable
* ethical
* honest
* honorable
* kosher
* principled
* reliable
* responsible
* righteous
* secure
* sensible
* straight
* true
* trusty
* truthful
* unfailing
Antonyms
* untrustworthy
faithfulness
English
Noun
(-)
The state of being faithful; allegiance; loyalty; fidelity.